Introduction to PHP

1. A. Chaubal 1 Introduction to PHP Amrish V. Chaubal Data & Knowledge Engineering Division amrish@ncst.ernet.in

2. A. Chaubal 2 Introduction to PHP PHP Hypertext Preprocessor. Other Names : Personal Home Page, Professional Home Page Is a server side scripting language. Capable of generating the HTML pages HTML generates the web page with the static text and images. However the need evolved for dynamic web based application, mostly involving database usage.

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4. A. Chaubal 4 Why PHP? ..there are no. of server side scripting available like ASP, SSJS, JSP�.. PHP involves simplicity in scripting (..generally using the database) platform independence. PHP is primarily designed for web applications well optimized for the response times needed for web applications Is an open source.

5. A. Chaubal 5 PHP Language features PHP language features such as control structures, operators, variable types, function declaration, class/object declaration are almost similar to any compiled or interpreted language such as C or C++.

6. A. Chaubal 6 PHP Data Type Three basic data types Integer Double String More data types Array Object PHP is an untyped language variables type can change on the fly.

7. A. Chaubal 7 PHP Block PHP code block is embedded within the <?php and ?> tags. When the server encounters the PHP tags it switches from the HTML to PHP mode. There are four different ways to embed the PHP code <?php echo(�Some PHP code�); ?> <? echo(�Some PHP code�); ?> <SCRIPT Language=�php�> echo(�Some PHP code�); </SCRIPT> <% echo(�Some PHP code�); %>

8. A. Chaubal 8 PHP Constants ..values that never changes Constants are defined in PHP by using the define() function. For e.g. define(�NCST�, �National Centre for Software Technology�) defined() function says whether the constant exists or not.

9. A. Chaubal 9 PHP Variables The variables in PHP are declared by appending the $ sign to the variable name. For e.g $company = �NCST�; $sum = 10.0; variable�s data type is changed by the value that is assigned to the variable. Type casting allows to change the data type explicitly.

10. A. Chaubal 10 PHP Variables (cont.) Rich set of functions for working with variable. For e.g gettype, settype, isset, unset, is_int, intval etc etc

11. A. Chaubal 11 PHP Operators All the operators such as arithmetic, assignment, Comparison, and logical operators are similar to the operators in C and C++. In PHP the string concatenation operator is denoted by �.�. For e.g. $name = �My name is�.$myname;

12. A. Chaubal 12 PHP Statements IF statement if (<condition>) { //php code goes here } else { //php code goes here } Alternative Syntax if(<condition>) : //html code goes here else : //html code goes here endif;

13. A. Chaubal 13 PHP Statements (cont.) For loop for($i=0;$i < 10;$++i) { echo(�the value is :�. $i); } Alternative Syntax for($i=0;$i < 10;$++i) : // html code goes here endfor; While loop Do-While loop

14. A. Chaubal 14 Functions Function declaration in PHP function my_func(<parameters>) { //do something in the function } for e.g. function sayHello() { echo(�<B>hello amrish<B><BR>�); }

15. A. Chaubal 15 Functions (cont.) Assigning functions to the variables for e.g $hello = �my_func�; to invoke the function my_func() through the variable $hello( ); When an argument is to be passed by reference, an ampersand (&) is placed before the parameter name for e.g. my_func(&$my_refvar);

16. A. Chaubal 16 Arrays ..contains value set each element has a value, data stored in the element. And has a key by which the element can be referred to.

17. A. Chaubal 17 Initializing Arrays No of ways to initialize the array. For e.g. $ncststaff[] = �amrish�; $ncststaff[] = �murali�; $ncststaff[] = �narayan�; $ncststaff[123] = �amrish�; $ncststaff[122] = �murali�; $ncststaff[121] = �narayan�; $ncststaff = array (�amrish�, �murali�, �narayan�); to change the indices of the array use => operator.

18. A. Chaubal 18 Accessing the Array Elements The elements in the array can be accessed by using the list and each constructs for e.g while(list($key,$value) = each(countries)) echo(�$value<BR>\n�); current(<arrayname>) gives the current value being accessed. key(<arrayname>) gives the index of the current element that is being accessed. prev(<arrayname>) gives the previous element. next(<arrayname>) gives the next element.

19. A. Chaubal 19 Accessing the Array Elements (cont.) Array_walk(<arrayname>,<function_name>) function_name is the function that is written for every member of an array. For e.g $ncststaff = array (�amrish�, �murali�, �narayan�); array_walk ($ncststaff, printstaff); // function to print each element of the array function printstaff($names) { echo �<B>$names</B><BR>\n�; }

20. A. Chaubal 20 Arrays (cont.) $ncststaff = array (�dake� => array(�amrish�, �lakshana�, �venkat�), �spc� => array(�narayan�, �murali�,�prasad�)); creates a two dimensional array. Sorting Functions sort() : sorts the elements in the numeric and alphabetical order. rsort() : sorts the elements in the reverse order. asort() : sorts the elements in the array without changing the indices. ksort() : sorts the arrays by key.

21. A. Chaubal 21 Classes Class is a template of an object and includes the properties and methods that describe an object and behavior. Class in PHP is defined using class statement.

22. A. Chaubal 22 Classes (cont.) For e.g <? class company { // define the properties var $companyname; // define the methods function company($cname) { $this->companyname = $cname; } function getnames($idcode) { //return the name of the employee for the required idcode } } ?>

23. A. Chaubal 23 PHP Richness PHP comes with myriad of options i.e. supports several APIs and interfaces to other programming tools such as Database connectivity. LDAP XML Mail protocols such as IMAP, SMTP Image functions etc�.

24. A. Chaubal 24 Support for Regular Expressions Not pretty things to look at and work with. E.g. ^.+@.+\\..+$ PHP takes over the headache from the programmers for explicitly coding for pattern matching. Functions: ereg() and eregi() ereg_replace() & eregi_replace() split()

25. A. Chaubal 25 Image Generation & Manipulation PHP offers powerful set of functions for generating and manipulating the images. Rendering regular geometric figures, modifying images manipulate text, font and color and even the pixels in the image. �.creating the images on the fly.

26. A. Chaubal 26 Image Generation & Manipulation (cont.) PHP uses the GD library for the most of the image functionality that it offers. GD library is used for generating the two-dimensional graphics. PHP API�s provides us with functions to: Create, delete, resize and modify images. Draw basic geometric figures Manipulate text and fonts Manipulate colors Interlace and manipulate pixels Handle PostScript files

27. A. Chaubal 27 Mailing functions Sending E-Mails Mail() Used to send simple text messages. Depends on the local mail delivery system. Using SMTP Accepts the e-mail for every recipient and goes through trouble of delivering the e-mails. Receiving E-Mails PHP works out well with the IMAP protocol. Rich set of support functions Imap_open, impa_delete, imap_close, imap_mail_copy, imap_mail_move etc.

28. A. Chaubal 28 PHP-Database Connectivity Supports APIs for accessing large number of databases. ODBC is a standard API for accessing a database that has PHP support.

29. A. Chaubal 29 PHP-Database Connectivity Some of Oracle 8.x functions. OCILogon OCILogoff OCIParse OCIFetch; OCIFetchInto; OCIFetchStatement OCIExecute OCIFreeStatement

30. A. Chaubal 30 LDAP Support in PHP PHP provides LDAP API�s that allows the programmers to create LDAP clients; by providing transparent access to backend LDAP directory servers. For e.g. Web based e-mail client. Telephone Directory.

31. A. Chaubal 31 XML Support in PHP PHP supports a set of functions that can be used for writing PHP-based XML applications. These functions are used for parsing well formed XML document.

32. A. Chaubal 32 References Professional PHP programming By Jesus Castagnetto, Chris Schollo et al www.phpbuilder.com www.php.net

33. A. Chaubal 33 THANK YOU